Exam 1 - Lecture 3 Flashcards

1
Q

Two components that determine cardiac output:

A

health of heart and health of system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

increase of resistance to venous return will cause

A

less venous return and less cardiac output

e.g. Right atrial pressure 0mmHg has 5L/min of venous return at Psf of 7, but if RA pressure is +4 its 2.5L/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If right atrial pressure increases, what needs to increase in order to raise venous return instead of lowering it?

A

Higher Psf. If it stays the same, then the delta P falls lower than 7 and it would decrease venous return.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is making the right atrial pressure negative not as effective as raising the right atrial pressure + also increasing Psf?

A

if its negative it can only go up to 6L/min bc the veins would collapse from the negative pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

If body needs to enhance CO for a marathon, it chooses to

A

Change the Psf!!!!

by tightening arteries to improve blood flow to muscles,

mesenteric arteries clamp down to shut down digestion

Increase BP

Increase venous constriction to raise Psf the most to improve blood returning to heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Primary obstacle to blood returning to heart would be

A

Chest full of air can compress the vena cavae and return in less venous return, such as during positive pressure ventilation. Counter this by tightening up veins with phenylephrine or more air per breath.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What medication can tighten up veins to produce more venous return to heart?

A

Phenylepherine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where does majority effect of phenylephrine work?

A

Tightens up the veins more than arteries, and only has to tighten up them a little bit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A hypoeffective heart will move the cardiac output curve to the

A

right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A hypereffective heart will move the cardiac output curve to the

A

left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

IF someone has a heart problem, what happens to their CVP, and why?

A

increased and its because the heart cant pump it all out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

If the heart is weakening, the catecholamines step up. but if its a long term issue, its scaled back and replaced by

A

volume retention and blood expansion at the kidneys. Norepi and epi increase water retention as well.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the max cardiac output if we maxed venous return but didnt do anything to the heart?

A

13L/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When the body wants to increase CO, the main thing the body adjusts is

A

venous return

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Output of the heart is geared by the

A

metabolic rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Conditions that increase metabolic rate/cardiac output (from highest increase of CO to lowest increase)

A

Beriberi, AV shunts, hyperthyroidism, Anemia, pulm disease, pagets disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Conditions that decrease metabolic rate

A

Removal of arms and legs, hypothyroidism (lowest metabolic demand).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When cardiac output is reduced due to less metabolic demand, what happens to peripheral resistance?

A

increased to allow less blood flow to tissues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When cardiac output is increased due to more metabolic demand, what happens to peripheral resistance?

A

Decreased to allow more blood flow to tissues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Beriberi

A

Vit B1 deficiency, makes cells much less efficient and need to use more energy now.

not common in US, usually only third world countries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why does vascular resistance reduce with AV shunts?

A

its one more route for the blood to take, reducing resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Cardiac output is tightly linked to

A

oxygen consumption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Dinitrophenol

A

old weight loss drug that would drive up metabolic rate

need nervous system to cooperate in order to boost cardiac output on this chart (????)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How does dinitrophenol help with blood pressure?

A

keeps blood pressure from crashing.

arteries dilate and veins will constrict to produce more venous return and cardiac output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what drugs should we not take

A

gas station drugs

26
Q

Cardiac index

A

L/min/M2

27
Q

What is a normal body surface area

A

1.7M2

28
Q

What is a normal Cardiac index for a healthy 20 year old 70kg patienrt

A

3L/min/M2

29
Q

what age does our cardiac index max out?

A

10 years old

30
Q

Whats a normal max cardiac index

A

4-5L/min/m2

31
Q

cardiac index of a reasonably healthy 70 year old man

A

2.4L/min/m2

32
Q

Why does our cardiac index lessen as we age?

A

less energy expenditure

33
Q

which side of the heart has a steeper cardiac curve?

A

right ventricle..

think right atrial pressure is 0 and left atrial pressure is 2

34
Q

CVP depends on where you measure.. right outside right atrium is ____ and then further from the heart the pressure gets _____

A

CLOSE to 0mmHg; higher due to DISTANCE

35
Q

Mean circulatory filling pressure is same as

A

Psf

36
Q

With an AV fistula, the filling pressure will be _____ and the cardiac output will be _______. Why?

A

normal;high; resistance to venous return is reduced

37
Q

Reducing resistance to half will increase or decrease venous return?

A

Increase

38
Q

During hemorrhagic shock, how does heart adjust?

A

increases right atrial pressure

39
Q

normal intrapleural pressure is

A

-4mmHg

40
Q

When right atrial pressure increases to +4, how does interpleural pressure change?

A

Becomes much higher, around +2mmHg

41
Q

-4mmHg is equal to how much cmH2O

A

-5

42
Q

When you take a breath, it sucks air into lungs but also

A

sucks blood into heart, therefore there is higher cardiac output

43
Q

During exhalation, how does this adjust cardiac output?

A

decrease because there is more pressure in the intrapleural space

44
Q

If there is increased intrathoracic pressure, there will be _____ cardiac output. Over time, the body will compensate by ____

A

reduced; increasing venous return by constricting the venous system

45
Q

If there is a hypoeffective heart with reduced intrapleural pressure (more negative) then the hypoeffective heart will have a _____ shift with a _____ plateau

A

Left cardiac output curve; lower

46
Q

A hypereffective heart with an increased intrapleural pressure will have what output shift and what plateau

A

Right shift; high plateau

47
Q

How do arterial specific vasodilators cause increased venous return? Does it alter Psf?

A

Relax the arterioles to relax the “chokepoint” which will increase the pressure downstream into the venules, which will push the blood faster to the right heart.

This does NOT change the Psf

48
Q

SVR is mainly governed where

A

arterioles

49
Q

Specific example of arterial specific vasodilator?

A

ACE-I

50
Q

Example of venous specific vasodilator is

A

nitroglycerin

51
Q

Do venous specific vasodilators change Psf?

A

yes, it will reduce it

52
Q

How does venous specific vasodilators change delta p?

A

lowers

53
Q

whats the main purpose/effect of nitroglycerin?

A

reducing preload and the stress on the heart so it needs less oxygen

54
Q

mixed vasodilators have what result on cardiac output?

A

dilates both vessels but since venous changes outweigh arterial, it slightly lowers venous return and Psf and therefore cardiac output

55
Q

If we reduce volume or increase venous compliance, the cardiac output will

A

decrease

56
Q

If we increase volume or decrease venous compliance, the cardiac output will

A

increase

57
Q

Decreased SVR will result in

A

increased CO

58
Q

Increased SVR will result in

A

decreased CO

59
Q

If the heart is damaged, then how will body adjust

A

Venous compliance reduces (veins tighten up), increased volume retention, and increased SVR

60
Q
A